Technical Field
The present invention relates to a wire connection structure in various kinds of coil devices, and for example, relates to a wire connection structure provided at a coil antenna as a coil device included in an engine start switch of a vehicle such as an automobile.
Related Art
There are various kinds of coil devices, but as an example thereof, a coil device of a solenoid valve (solenoid) included in an engine control mechanism of an automobile is illustrated in FIG. 11.
As illustrated, the coil device includes a coil 12 formed by winding copper wire around a cylindrical portion of a bobbin 11, and first and second terminals 13, 14 each having long narrow shape and integrally fixed to a bobbin flange 11a. 
Further, in the coil device, first and second entwining portion 13a, 13b are formed at two places at an outer edge of the first terminal 13, and further a fusing portion (thermal caulking portion) 13c is formed between the first and second entwining portions 13a, 13b. In the same manner, first and second entwining portions 14a, 14b and a fusing portion 14c are provided at the second terminal 14.
In the coil 12 of the above-described coil device, a winding start portion 12a of the coil 12 is first entwined at the second entwining portion 13b of the first terminal 13, and subsequently passed through the fusing portion 13c, and then entwined at the first entwining portion 13a. After that, the winding start portion 12a is led to and wound around the cylindrical portion of the bobbin 11, thereby forming the coil 12.
Further, a winding end portion 12b of the coil 12 is led out from the bobbin 11 and entwined at the first entwining portion 14a of the second terminal 14, and subsequently passed through the fusing portion 14c, and then entwined at the second entwining portion 14b. 
Further, the winding start portion 12a passed through the fusing portion 13c is fixed to the first terminal 13 by applying thermal caulking to the fusing portion 13c as illustrated in FIG. 12. In the same manner, the winding end portion 12b passed through the fusing portion 14c is fixed to the second terminal 14 by applying thermal caulking to the fusing portion 14c. 
Meanwhile, a connecting portion 13d of the first terminal 13 and a connecting portion 14d of the second terminal 14 are electrically connected to a circuit board provided at a control mechanism.